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Re: references and dependency

From: Steven Pemberton <steven.pemberton@cwi.nl>
Date: Wed, 08 Feb 2017 11:01:04 +0100
To: "Erik Bruchez" <ebruchez@orbeon.com>
Cc: XForms <public-xformsusers@w3.org>
Message-ID: <op.yvb532mssmjzpq@steven-aspire-s7>
On Wed, 08 Feb 2017 01:04:27 +0100, Erik Bruchez <ebruchez@orbeon.com>  

> I am not sure that it is very useful to cover all the details of what  
> changes to the data model can affect >the result of an expression, or to  
> make a distinction between nodes which are referenced or not during  
> >expression evaluation. This can even depend on how optimized an XPath  
> processor might be.
If it depends on how it is implemented, then I agree it has no place in  
the spec.

> It should be enough to say that there are expressions with dynamic  
> dependencies, provide examples, and >indicate that manual rebuilds are  
> needed in such cases.
Do you think it is possible to create a canonical set of examples that  
show when manual rebuilds are needed?

> By the way, it is certainly possible to improve on the above. For  
> example, allowing MIPs to be part of the >dependency graph would be  
> useful.
Can you give an example?


>  -Erik
> [^typed-values]: With XPath 2, it can be also be a *typed value*. A  
> typed value also comes from the text >content so that doesn't make a  
> difference for this discussion.
> On Wed, Jan 25, 2017 at 4:12 AM, Steven Pemberton  
> <steven.pemberton@cwi.nl> wrote:
>> There is some duplication of definitions.
>> Recalculate
>> defines 'reference' 'dependent' 'circular dependency'
>> https://www.w3.org/community/xformsusers/wiki/XForms_2.0#Recalculate
>> Expressions > References, Dependencies, and Dynamic Dependencies
>> defines 'references' 'dependent' 'dynamically dependent'
>> https://www.w3.org/community/xformsusers/wiki/
>> XForms_2.0#References.2C_Dependencies.2C_and_Dynamic_Dependencies
>> So I plan to bring these together, and merge them.
>> However, the latter section distinguishes dependency for computed  
>> expressions and other expressions. In >>particular a computed  
>> expression has to use the content of a node to be dependent on it,  
>> while other >>expressions are dependent on it regardless.
>> "A computed expression is *dependent* on an instance node if it  
>> references it and uses its character >>content (rather than just  
>> referencing for navigation); any other expression is dependent on an  
>> instance >>node if it just references it."
>> Recalculate doesn't make this distinction.
>> Which is right?
>> Steven
Received on Wednesday, 8 February 2017 10:01:45 UTC

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